Single-Axis Lens Units for Low-Cost Multicore Fibre Alignment
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Solution Overview
Problem
Conventional fibre-optic communication systems face high manufacturing costs due to the need for precise alignment and costly components like single-mode and multi-mode lasers and silicon-germanium receivers, and suffer from chromatic dispersion issues that limit transmission distance and require complex digital circuitry for modulation and decoding.
Innovation Solution
An optical transmitter unit with an array of micro-LEDs and a controller using analogue circuitry for OOK coding, coupled with an optical filter to reduce chromatic dispersion, and a photodetector array with CMOS sensors, allowing parallel data transmission over multiple channels using commodity components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional fibre-optic communication systems use single-mode and multi-mode lasers with silicon-germanium receivers, then transmission bandwidth can be maximized, but manufacturing cost increases significantly due to precise alignment requirements and expensive components
Solution Approach 1:
The patent replaces expensive single-mode and multi-mode lasers with inexpensive visible light LEDs, and uses standard polymer optical fibre instead of costly glass fibre. This substitution maintains adequate transmission bandwidth while dramatically reducing component costs and eliminating the need for specialized alignment procedures during manufacturing.
Solution Approach 2:
The patent changes the operating wavelength from infrared (conventional) to visible light spectrum, specifically using LEDs with wavelengths between 450-650nm. This parameter change enables the use of cost-effective visible light components while achieving sufficient bandwidth for the intended application, thereby resolving the contradiction between bandwidth and manufacturing cost.
2Productivity
If conventional systems use complex digital coding schemes such as PAM4 or OFDM to maximize bandwidth, then data transmission capacity increases, but device complexity and cost increase due to expensive digital circuitry
Solution Approach 1:
The patent extracts and eliminates the complex digital signal processing components (encoders and decoders) from the system. By using simple intensity modulation and direct detection with visible light LEDs, the system achieves adequate bandwidth without requiring complex digital coding schemes like PAM4 or OFDM, thereby reducing device complexity and cost.
Solution Approach 2:
The patent replaces complex digital modulation and decoding systems with a simpler optical-based solution using intensity-modulated visible light and direct detection. This substitution eliminates the need for expensive digital circuitry while maintaining sufficient transmission capacity through the use of multiple parallel channels.
3Productivity
If visible light signals are transmitted at higher speeds, then data bandwidth increases, but chromatic dispersion increases causing signal overlap and interference, which limits transmission distance
Solution Approach 1:
The patent divides the transmission system into multiple independent parallel channels, each using a separate LED and photodetector pair. This segmentation allows each channel to operate at lower speeds with better signal integrity, while the aggregate bandwidth is increased through parallel transmission. This resolves the contradiction by distributing the bandwidth requirement across multiple reliable channels rather than relying on a single high-speed channel that would suffer from severe chromatic dispersion.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables cost-effective, high-bandwidth communication over longer distances by reducing chromatic dispersion and eliminating the need for complex digital signal processing, while using affordable components like CMOS sensors and polymer optical fibre cables.
Implementation Method 1
different colours of visible light travel at different rates through the fibre, potentially causing overlap or interference between signals. Higher speed transmission increases chromatic dispersion
Implementation Method 2
an optical filter configured to reduce chromatic dispersion
Implementation Method 3
encode and transmit the data by modulating the visible light output by the array of light sources
Implementation Method 4
transmit visible light along a respective core of the multicore fibre optic cable for receipt at a corresponding photodetector array
Data Source
AI summary
A lens unit for an optical transmitter unit receives visible light emitted from an array of light sources of optical transmitter unit. The lens unit then directs the visible emitted from the array of light sources into a plurality of cores of a multicore fibre optic cable connectable between the optical transmitter unit and an optical receiver unit. The lens unit comprises a single axis of optical symmetry. The lens unit can be included in an optical transmitter unit or an optical transceiver unit.